The present invention relates to weed control blocks laid on the boundary of a sidewalk to prevent the propagation of weeds. The present invention also relates to a weed control structure suitable for blocks laid on the boundary of a sidewalk.
As shown for example in FIG. 6, a conventional concrete apron block 60 is installed on a boundary dividing a roadway 70 and a sidewalk 75. The apron block 60 has an approximately L-shaped cross-section. In the roadway 70, gravel 71 and asphalt 73 are laid; in the sidewalk 75, gravel 77 and asphalt 79 are laid.
Incidentally, the thicknesses of the gravel 77 and asphalt 79 in the sidewalk 75 are smaller than those of the gravel 71 and asphalt 73 in the roadway 70.
Therefore, the conventional apron block 60 suffers from some problems. If seeds of weeds 80 germinate in a gap a produced in the boundary between the apron block 60 and the asphalt 79, the roots 81 of the weeds 80 readily reach the soil 83 through short distances. As the years pass, the weeds 80 spread deep root and become eyesores. The weeds 80 narrow the effective width of the sidewalk 75 and cause the mowing cost to increase. The weeds 80 also cause the asphalt 79 to be cracked and make the surface of the asphalt 79 unfavorably raised.
One approach to solve the above-described problems is as follows. As shown in FIG. 7, an apron block 60-2 is provided with a notch-shaped step portion 65 longitudinally extending along an upper end edge of the apron block 60-2 which is closer to the sidewalk 75. Asphalt 79 is placed so as to cover the step portion 65, thereby increasing the distance H traveled by the roots 81 of the weeds 80 entering through the gap a to reach the soil 83, and thus making it difficult for the weeds 80 to spread.
However, some of the fertile weeds 80 still take root through the gap a. Therefore, there has been a demand for appearance of a block capable of preventing the propagation of weeds even more effectively.